Flash lamp manufacture



1967 R. M. ANDERSON FLASH LAMP MANUFACTURE Filed April 50, 1965 lnventov: RObEET I LATWdEFSQTW 5 i His ATFOT'TWEH United States Patent3,304,144 FLASH LAMP MANUFACTURE Robert M. Anderson, Euclid, Ohio,assignor to General Electric Company, a corporation of New York FiledApr. 30, 1965, Ser. No. 452,190 7 Claims. (Cl. 31620) This inventionrelates to a method of producing a photoflash lamp comprising a sealedglass bulb containing a quantity of readily combustible light-producingmaterial in the form of sheet foil and a filling of a combustion-supporting gas which, on ignition of the combustible material,reacts therewith to produce a momentary flash of actinic light of highintensity. More particularly, this invention relates to a method ofinserting sheet foil combustible material in the shape of a cup ito suchflash lamps during lamp manufacture.

Photoflash lamps that can be made by the process of the presentinvention are described and claimed in copending application Serial No.452,189Anderson, filed concurrently with the present application. Thoseflash lamps are to some extent and for some purposes modifications ofand improvements over photoflash lamps described and claimed in Patent2,982,119Anderson which, in turn, canbe made by the processes ofapplication Serial No. 91,279Anderson, filed December 3, 1963, nowPatent 3,188,162, issued June 8, 1965. The patent and both of theapplications are assigned to the assignee of the present application.Due to the relationships among these inventions, details of variousequivalent acceptable methods of manufacture of flash lamps claimed inPatent 2,982,119 are described in Patent 3,188,162.

The flash lamps of application Serial No. 452,189 differ from those ofPatent 2,982,119 in one basic way in that they contain sheet foil havinga configuration and dimensions great enough that the foil resilientlycontacts the inner wall of the flash bulb tending to hold the foil inposition. In a similar manner, the method of manufacture of the presentinvention differs from that of Patent 3,188,162 in one principal mannerin the process of loading the sheet foil combustible material into thelamp.

It is an object of the present invention to provide a method ofmanufacture for producing flash lamps of a tubular type containing sheetfoil combustible material.

Another object of the invention is to provide such a process for lampsin which the sheet foil combustible material is in the form of a cupwhich opens towards ignition means in the lamp,

Still another object of the invention is to provide such a process forproducing flash lamps in which the sheet foil combustible material isfolded into the shape of a cup which is substantially further from theignition means during sealing and afterwards than is filamentarycombustible material also present in the flash lamp.

Still another object of the invention is to provide a process forproducing tubular flash lamps containing both filamentary and sheet foilcombustible material in which the sheet foil has a predeterminedconfiguration and location within the lamp and is in contact with areasof the lamp wall.

Further objects and advantages of the invention will appear from thefollowing detailed description of species thereof and from theaccompanying drawing.

In the drawing, FIG. 1 is a partially sectioned front elevational viewof a flash lamp made according to the invention.

FIG. 2 is a schematic illustration of several steps of the inventionconstituting a change from prior art methods of making flash lamps.

FIG. 3 is a side elevational view of a flash lamp in 3,304,144 PatentedFeb. 14, 1967 manufacture according to one aspect of the invention afterinsertion of a foil cup and prior to final sealing by tipping off.

Briefly stated, the present invention in one embodiment provides aprocess for producing tubular photoflash lamps containing sheet foilcombustible material in the form of a cup opening towards ignition meansin the lamp. The process comprises the addition of certain steps toprior art processes of manufacturing photoflash lamps containing onlyfilamentary combustible material such as described and claimed in Patent3,188,162. The process of the present invention is applicable to themanufacture of flash lamps containing only sheet foil as the combustiblematerial as well as to flash lamps containing a combination of bothsheet foil and filamentary combustible material, which are described andclaimed in copending application Serial No. 452,189. In the case ofmanufacturing photoflash lamps containing both filamentary combustiblematerial and sheet foil combustible material the filamentary combustiblematerial is added first to the open end of the lamp and positioned inproximity to the closed end of the lamp through which the leadin wiresare sealed before adding the sheet foil. Thus, the filamentarycombustible material will be generally closer to the ignition means thanis the sheet foil. In this way, the filamentary material can aid inkindling the ignition of the sheet foil material. The additional stepsthat can be added to the processes of the prior art for the practice ofthe present invention follow: forming a foil cup from a sheet foil blankby pushing the blank into one end of a thin-wall tube, positioning thethinwall tube in relation to a glass lamp tube which has ignition meanscom-prising lead-in wires sealed through one end with the forming tubeeither adjacent to or within the lamp tube, and causing the foil cup tomove from the forming tube into the lamp tube. The foil cup is then inclose proximity to and opens toward the ignition means which are nearthe sealed end of the lamp tube. Subsequently, the lamp manufacture iscompleted by exhausting the lamp, filling the lamp with acombustion-supporting gas, and sealing off the lamp which may be done inany of the various ways known in the art.

The present invention not only provides a method for loading a piece ofsheet foil combustible material into modern miniature photoflash lamps,but also allows a large degree of reproductibility at high manufacturingspeeds. This is due in part to the foil cup having a predeterminedgeometry and position in the lamp and supporting itself on the innerwall of the lamp by resilient contact with the inner wall of the lamp,generally area rather than point contacts. Also, when filamentarycombustible material, such as shredded foil, is present in the flashlamp in addition to the sheet foil, the foil cup serves to envelop,compact and hold in place the filamentary combustible material,preventing it from possibly being caught in the glass seal when the lampis finally closed by tipping off.

Referring now to the drawing, FIG. 1 illustrates one construction of aphotoflash lamp of the invention. Aside from the use of sheet foilmaterial, the flash lamp illustrated is generally of a type described indetail in Patent 2,982,119. In general terms, the lamp comprises a stempress base 1 having electrical leads sealed therein, the externalportions of which are retroverted and sealed back into the stem press asat 3 and folded back over opposite sides of the stem press at 4 toprovide electrical contacts. The stem press base generally has acontinuouly transverse slot 5 at one side to facilitate handling andutilization of the lamps. This base structure is described in furtherdetail in Patent 3,016,727Vanden 3 Boom et al., assigned to the assigneeof the present invention. Y e l The inner portions 2A of the lead wires2 are held in position by a glass bead 6 and are electrically connectednear their innermost ends by a filament such as of tungsten ortungsten-rhenium alloy wire. On the lead wires and the filament islocated a fulminating primer material 8 which supplies ignition means toinitiate the flashing of the lamp on the input of an electrical currentthrough filament 7. Filament 7 heats very rapidly causing thefulminating primer to ignite. This ignition in turn causes the rapidcombustion of filamentary combustible material 9 within the photoflashlamp-which, in turn, ignites the sheet foil combustible material 14.

The wall of. the lamp is formed from glass tubing 10, the base 1 havingbeen formed at one end of the tubing. The other end of'the tubing isnarrowed down at 11 to allow closure by formation of tip 12 after therest of the assembly of. the inner parts of the lamp. After tipping, theflash lamp can be covered with a protective lacquer 13 as a safetyfeature to prevent explosion on flashing the lam A foil cup 14 ofzirconium foil has been formed and positioned over the filamentarymaterial 9, between the filamentary material 9 and the tip 12. The openend of the cup faces the ignition means which comprises the filament 7and the fulminating primer 8. The foil cup 14 has a number of ears 15that have been folded from the foil material in the production of thecup. These ears contact areas of the inner surface of the glass bulbwall giving some resilient support to the foil cup and tending to holdit in position.

FIG. 2 schematically illustrates a novel portion of the manufacturingprocess of the invention. As shown in position A, a sheet foil blank 20is provided and positioned above a thin-wall forming tube 21. Inposition B, the sheet foil blank has been pushed into the forming tube21 to form a foil cap 22. A plunger 26 slightly narrower than theforming tube would be satisfactory for pushing the foil blank 20 intothe forming tube 21. Ears 23 will be left sticking out from the foil capas shown if the foil blank 20 had angular corners such as a square foilblank would. On the other hand, if the foil blank used were round, theoperation of pushing it into the forming tube 21 might cause the sidesof the cup to have more of a corrugated configuration rather thanfolding relatively neatly into an earred cup.

At position C, the forming tube 21 is shown inserted into a lamp tube 24with the end of the forming tube 21 containing the foil cap 22 in closeproximity to ignition means 25 that have been provided thus far in themanufacture of the flash lamp. As described in connection with FIG. 1, abase 1 is illustrated as having been previously formed on the flashlamp. Lead wires 32 are shown prior to being bent down to provideelectrical contacts as at 4 in FIG. 1. Also shown in this embodiment isa quantity of filamentary combustible material such as shreddedzirconium foil made in accordance with the teachings of Rippl et al.Patent 2,351,290.

At D is shown a lamp tube of the invention in which foil cup 22 has beenexpelled from forming tube 21 into lamp tube 24 with ears 23 makingresilient contact with the inner walls of the bulb tending to hold thefoil cup 22 in position. The. forming tube 21 shown in position C hasnow been removed from the lamp tube, and the lamp tube 24 is now readyfor further processing to complete its manufacture into a flash lamp. Itwill be understood that any appropriate means could be used to causefoil cup 22 to move out of the forming tube 21 and into the lamp tube24. Plunger 27 is adapted to push the foil cup 22 into position.Suitable means might also include blowing with a stream of air or othergas.

FIG. 3 illustrates a further step in one process of manufacture of aflash lamp from lamp tube 24. As described more fully in Patent3,188,162, the combustible material which, in this case, comprisesfilamentary shredded foil 9 in addition to sheet foil cup 22, iscompressed into the lamp tube 24 somewhat away from the area 28 at whichthe lamp tube is heated and formed to make a dome before sealing bytipping ofi, This compression of the combustible material away from theglass to be heated for forming and tipping can be accomplished in thestep in which the foil cup 22 is placed into the lamp tube 24.

After formation of the dome at 28, the lamp tube may be exhausted andthen filled with a combustion-supporting gas through the necked downregion 29 from apparatus which can be readily connected to tube 30. Asis known in the art, various combustion-supporting gases may be used inphotoflash lamps. Normally, they are oxygenous, although other gasessuch as carbon disulfide.

as shown in Patent 2,791,897Roth, assigned to the assignee of thepresent invention, can be used in certain circumstances. Alternatively,the lamp tube 24 can be broken off in the neck 29 and exhausting andfilling accomplished by other means such as by operating on the lamp inan airtight chamber by evacuating the chamber.

and then filling it with the desired gas. Subsequently, the lamp tube 24is sealed by tipping off at 31.

Aside from the novel method of forming foil cap 22 and inserting it intothe lamp tube 24, other satisfactory techniques can be used for thepreceding and succeeding portions of the lamp manufacturing process.

Stated in general terms, the overall process in which the process of theinvention is used comprises the steps of sealing a lamp mount structurecomprising a pair of lead-in wires in one end of a glass lamp tube toform a sealed end thereon, applying through the other end of said lamptube a quantity of primer material, e.g., fulminating material, onto aportion of said lead-in wires within said lamp tube to form an ignitionmeans, forming and placing inside the lamp according to the invention asheet foil cup of combustible material, exhausting and introducing intothe lamp tube through its open end a combustionsupporting gaseousmedium, and then heating and sealing off the lamp tube at a positionfurther from the sealed end than is the foil cup. Other embodiments ofthe invention provide for placing filamentary combustible materialwithin the flash lamp before adding the foil cup, the requirement of afilament as part of the ignition means, and sealing off the lamp tube inan intermediate portion of its length located between its open end andthe combustible foil material. In each case, the sheet foil combustiblematerial has a configuration and dimensions larger than the innertransverse dimensions of the lamp tube so that the foil resilientlycontacts the inner surface of the flash lamp tending to hold the foil inposition. Preferably, the resilient contact is made with areas of theinner surface of the flash lamp. When filamentary combustible materialis used inaddition to a sheet foil cup, the filamentary material islocated proximate to the ignition means and envelops the same. Thisplaces the filamentary material in closer proximity to the ignitionmeans than is the sheet foil cup, thereby allowing the fila-. mentarymaterial to aid in igniting the foil cup.

While specific examples have been given of the process of the invention,it will be understood that various changes, omissions and substitutionsmay be made within the true spirit and scope of the invention as definedin the appended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. The method of making a flash lamp comprising the steps of sealing alamp mount structure comprising a pair of lead-in wires into one end ofa glass lamp tube to form a sealed end thereon, applying through theopen other end of said lamp tube a quantity of primer material onto aportion of said lead-in wires Within said lamp tube to form an ignitionmeans, forming a foil cup of sheet foil combustible material outside ofsaid flash lamp by pushing a foil blank into a first end of a thin wallforming tube in one direction, said foil blank having dimensions in theplane of said foil substantially greater than the inside dimensions ofsaid forming tube so that said foil blank is folded into a generallycup-shaped configuration on being pushed into said forming tube, saidforming tube having transverse inner dimensions no larger than thetransverse inner dimensions of said flash lamp, positioning the firstend of said forming tube at least as close as adjacent to and alignedwith said lamp tube, and causing said foil cup to move in the directionopposite said one direction out of said first end of said forming tubeand through the open end of said lamp tube to a position proximate tothe sealed end of said lamp tube so that said foil cup opens toward saidignition means, exhausting and introducing into the said lamp tubethrough its said open end a combustion-supporting gaseous medium, andthen heating and sealing off said lamp tube at an area further from saidscaled end than is said foil cup.

2. The method of claim 1 in which filamentary combustible material isinserted into the lamp tube before the foil cup is moved into the lamptube so that said foil cup is generally further removed from theignition means than is said filamentary combustible material.

3 The method of making a flash lamp comprising the steps of sealing alamp mount comprising lead-in wires having a filament connectedthereacross into one end of a glass lamp tube to form a sealed endthereon with said filament located a short distance inwardly of the lamptube from its sealed end, applying through the open other end of saidlamp tube a quantity of primer material onto the filament and theadjacent portions of said lead-in wire to form an ignition means,forming a foil cup of sheet foil combustible material outside of saidflash lamp by pushing a foil blank into a first end of a thin wallforming tube in one direction, said foil blank having dimensions in theplane of said foil substantially greater than the inside dimensions ofsaid forming tube so that said foil blank is folded into a generallycup-shaped configuration on being pushed into said forming tube, saidforming tube having transverse inner dimensions no larger than thetransverse inner dimensions of said flash lamp, positioning the firstend of said forming tube at least as close as adjacent to and alignedwith said lamp tube, and causing said foil cup to move in the directionopposite said one direction out of said first end of said forming tubeand through the open end of said lamp tube to a position proximate tothe sealed end of said lamp tube so that said foil cup opens toward saidignition means, exhausting and introducing into said lamp tube throughits said open end a combustion-supporting gaseous medium, and thenheating and sealing off an intermediate portion of the length of saidlamp tube located between its said open end and the said combustiblefoil material.

4. The method of claim 3 in which filamentary combustible material isinserted into the lamp tube before the foil cup is moved into the lamptube so that said foil cup is generally further removed from theignition means than is said filamentary combustible material.

5. In a method of making a flash lamp comprising a glass lamp tube withignition means sealed into one end thereof and having its other end openduring manufacture and which contains sheet foil combustible materialhaving a configuration and dimensions great enough so that the foilresiliently contacts areas of the inner surface of said flash lamptending to hold the foil in position, the steps of:

(a) Forming a sheet foil blank which has dimensions in the plane of thefoil blank greater than the transverse inner dimensions of said lamptube,

(b) Pushing said sheet foil blank into a forming tube to form a foilcup, said forming tube having transverse inner dimensions no larger thanthose of said lamp tube,

(c) Positioning said forming tube at least as close as adjacent to andaligned with said open end of said lamp tube,

(d) Causing said foil cup to move into said lamp tube so that said foilcup opens towards said ignition means,

(e) Removing said forming tube from said lamp tube,

and

(f) Exhausting, filling with a combustion-supporting gas, and sealingsaid flash lamp.

6. In a method of making a flash lamp comprising a glass lamp tube withignition means sealed into one end thereof and having its other end openduring manufacture and which contains sheet foil combustible materialhaving a configuration and dimensions great enough so that the foilresiliently contacts areas of the inner surface of said flash lamptending to hold the foil in position, the steps of:

(a) Inserting filamentary combustible material into said lamp tube atthe sealed end to envelop said ignition means, and

(b) Forming a sheet foil blank which has dimensions in the plane of thefoil blank greater than the transverse inner dimensions of said lamptube,

(c) Pushing said foil blank into a forming tube to form a foil cup, saidforming tube having inner transverse dimensions no larger than those ofsaid lamp tube,

(d) Positioning said forming tube at least as close as adjacent to andaligned with said open end of said lamp tube,

(e) Causing said foil cup to move into said lamp tube so that said foilcup opens towards said ignition means and is generally further removedfrom said ignition means than is said filamentary combustible material,

(f) Removing said forming tube from said lamp tube,

and

(g) Exhausting, filling with a combustion-supporting gas and sealingsaid flash lamp.

7. In the manufacture of a flash lamp comprising a glass lamp tubehaving ignition means sealed in a closed end thereof and having itsother end open during manufacture, the steps which comprise forming asheet foil blank of larger size than the diameter of said lamp tube,pushing said foil blank into one end of a forming tube which is of adiameter to fit snugly in said lamp tube to form a foil cup in said endof the forming tube, inserting said forming tube into the open end ofsaid lamp tube with said one end of the forming tube foremost, andexpelling said foil cup from the forming tube to cause it to be 10-cated in the lamp tube adjacent to and opening toward said ignitionmeans.

No references cited.

RICHARD H. EANES, JR., Primary Examiner.

1. THE METHOD OF MAKING A FLASH LAMP COMPRISING THE STEPS OF SEALING ALAMP MOUNT STRUCTURE COMPRISING A PAIR OF LEAD-IN WIRES INTO ONE END OFA GLASS LAMP TUBE TO FORM A SEALED END THEREON, APPLYING THROUGH THEOPEN OTHER END OF SAID LAMP TUBE A QUANTITY OF PRIMER MATERIAL ONTO APORTION OF SAID LEAD-IN WIRES WITHIN SAID LAMP TUBE TO FORM AN IGNITIONMEANS, FORMING A FOIL CUP OF SHEET FOIL COMBUSTIBLE MATERIAL OUTSIDE OFSAID FLASH LAMP BY PUSHING A FOIL BLANK INTO A FIRST END OF A THIN WALLFORMING TUBE IN ONE DIRECTION, SAID FOIL BLANK HAVING DIMENSIONS IN THEPLANE OF SAID FOIL SUBSTANTIALLY GREATER THAN THE INSIDE DIMENSIONS OFSAID FORMING TUBE SO THAT SAID FOIL BLANK IS FOLDED INTO A GENERALLYCUP-SHAPED CONFIGURATION ON BEING PUSHED INTO SAID FORMING TUBE, SAIDFORMING TUBE HAVING TRANSVERSE INNER DIMENSIONS NO LARGER THAN THETRANSVERSE INNER DIMENSIONS OF SAID FLASH LAMP, POSITIONING THE FIRSTEND OF SAID FORMING TUBE AT LEAST AS CLOSE AS ADJACENT TO AND ALIGNEDWITH SAID LAMP TUBE, AND CAUSING SAID FOIL CUP TO MOVE IN THE DIRECTIONOPPOSITE SAID ONE DIRECTION OUT OF SAID FIRST END OF SAID FORMING TUBEAND THROUGH THE OPEN END OF SAID LAMP TUBE TO A POSITION PROXIMATE TOTHE SEALED END OF SAID LAMP TUBE SO THAT SAID FOIL CUP OPENS TOWARD SAIDIGNITION MEANS, EXHAUSTING AND INTRODUCING INTO THE SAID LAMP TUBETHROUGH ITS SAID OPEN END A COMBUSTION-SUPPORTING GASEOUS MEDIUM, ANDTHEN HEATING AND SEALING OFF SAID LAMP TUBE AT AN AREA FURTHER FROM SAIDSEALED END THAN IS SAID FOIL CUP.